| 摘要 |
A pneumatic radial tire for heavy load vehicles comprising a body reinforcement and a bead portion reinforcement, in which the bead portion reinforcement substantially continuously covers the carcass ply wound around a bead core up to the inside of the tire, the upper end of the turn-up portion of the carcass ply and the outside upper end of the bead portion reinforcement covering the upper end of the carcass ply are arranged at an area other than a bead portion flexible region defined by two segments BC and AD as shown in attached FIG. 3, the bead portion reinforcement makes use of a cord having a modulus which corresponds to 15 to 60% of that of the ply cord of the carcass, and a tension at 100% elongation of a soft stiffener corresponds to 5 to 30% of that of a hard stiffener, the soft and hard stiffeners being disposed on the bead core one upon the other. |
